B.S. Patel D. Dickinson C.M. Roach H.R. Wilson
Spherical tokamaks (STs) have been shown to possess properties desirable for a fusion power plant such as achieving high plasma β and having increased vertical stability. To understand their confinement properties in a reactor relevant regime a 1GW fusion power spherical tokamak plasma equilibrium was analysed using linear gyrokinetics to deter…
Preprint PublishedG. M. Staebler E. Belli J. Candy J. E. Kinsey H. Dudding B. Patel
The verification and calibration of a new quasi-linear transport model with a large database of gyrokinetic turbulence simulations is presented in this paper. In a previous paper [1], a model for the saturated spectrum of electric potential fluctuations was developed based on the properties of the non-linear 3D spectrum. In this paper, a modificat…
Preprint PublishedG. M. Staebler J. Candy E. Belli J. E. Kinsey N. Bonanomi B. Patel
The findings of an investigation into the properties of the three dimensional (3D) saturated fluctuation intensity of the electric potential in gyrokinetic turbulence simulations is presented. Scans in flux surface elongation and Shafranov shift are used to isolate the tokamak geometric dependencies. The potential intensity required in order to …
Preprint PublishedB. Patel C. Challis D. Dickinson L. Garzotti F. Koechl C. Roach G. Staebler H. Wilson
Spherical Tokamaks (STs) could provide a route towards a compact fusion reactor due to advantageous properties such as high plasma beta. A GW-scale ST plasma is explored where Q=10 and R=2.5m. In this design 110 MW of NBI is needed to provide 9 MA of noninductive current, where the remaining 12 MA is pressure driven. To penetrate into the core a 1 …
Preprint PublishedStuart I. Muldrew Hanni Lux Tim C. Hender Bhavin Patel Peter J. Knight Garry M. Voss Howard R. Wilson
Spherical Tokamaks offer a number of potential advantages for a future fusion power plant. They have a high ratio of thermal to magnetic field pressure (beta) and strong flows, either of which could result in reduced turbulence. Fewer Toroidal Field (TF) coils and a different geometry offers the potential for new methods of remote maintenance …
Preprint PublishedD. Patel M.D. Richardson B. Jim S. Akhmadaliev R. Goodall A.S. Gandy
A novel multicomponent alloy, V2.5Cr1.2WMoCo0.04, produced from elements expected to favour a BCC crystal structure, and to be suitable for high temperature environments, was fabricated by arc melting and found to exhibit a multiphase dendritic microstructure with W-rich dendrites and V-Cr segregated to the inter-de…
Preprint PublishedS. S. Henderson L. Garzotti F.J. Casson D. Dickinson M. O'Mullane A. Patel C.M. Roach H.P. Summers H. Tanabe M. Valovic MAST team
Carbon and nitrogen impurity transport coefficients are determined from gas puff experiments carried out during repeat L-mode discharges on the Mega-Amp Spherical Tokamak (MAST) and compared against a previous analysis of helium impurity transport on MAST. The impurity density profiles are measured on the lowfield side of the plasma, therefore this…
Preprint PublishedI.T. Chapman J.T. Holgate N. Ben Ayed G. Cunningham C.J. Ham J.R. Harrison A. Kirk G. Mcardle A. Patel R. Scannell The Mast Team
When resonant magnetic perturbations are applied in MAST, the plasma edge boundary experiences a three dimensional distortion, which can be a few percent of the minor radius in amplitude, in good agreement with ideal 3d equilibrium modelling. This displacement occurs in plasmas both with radial position feedback control applied, and without feedbac…
PublishedS. S. Henderson L. Garzotti F. J. Casson D. Dickinson M. F. J. Fox M. O’Mullane A. Patel C. M. Roach H. P. Summers M. Valovic The Mast Team
Time-dependent helium gas puff experiments have been performed on the Mega Ampere Spherical Tokamak (MAST) during a two point plasma current scan in L-mode and a confinement scan at 900 kA. An evaluation of the He II spectrum line induced by charge exchange suggests anomalous rates of diffusion and inward convection in the outer regions of both L-m…
PublishedM Valovic G Cunningham L Garzotti C Gurl A Kirk G Naylor A Patel R Scannell The Mast Team
Shallow fuelling pellets are injected from the high field side into plasmas in which ELMs have been mitigated using external magnetic perturbation coils. The data are compared with ideal assumptions in the ITER fuelling model, namely that mitigated ELMs are not affected by fuelling pellets. Firstly it is shown that during the pellet evaporation an …
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